This invention relates to irrigation hoses made of synthetic resin and particularly, to such hoses having integrally formed plurality of fluid passages.
The main application of the present invention is its use in irrigation of such plants as grapevine, where partial rootzone drying is employed. Researches performed in this respect show that such rootzone drying that is obtained by withholding the irrigation in a controlled manner, improves water use efficiency while maintaining crop yield and quality. These researches have been reported by P. R. Dry et al, for example in xe2x80x9cVine manipulation to meet fruit specificationxe2x80x9d, in Proceedings 10th Australian Wine Industry Technical Conference, Sydney, Australia, 208-241, 1999; and xe2x80x9cPartial rootzone drying-updatexe2x80x9d, the Australian Grapegrower and Winemaker, Annual Technical Issue 2000, 35-39.
As described in the above papers, the authors used in their researches standard drip emitters two per vine, for the irrigation thereof in turn on two sides of the vine so that when one side of the vine is watered the other one is allowed to dry. The emitters were placed on two sub-surface drip lines on each side of the vine row at a certain depth and distance from the center of the row.
Suggestions have also been made to dispose similar parallel drip lines above the ground along the rows of vine shoots at a certain height therefrom.
With the disposition of the drip lines in the manners described above, it is important that the emitters irrigating each vine and, consequently, the drip lines carrying the emitters, be fixed and accurately maintained in a predetermined mutual disposition, which is not easy to achieve.
According to the present invention, there is provided an irrigation system comprising an irrigation hose made of synthetic resin and having at least two integrally formed elongated irrigation lines, each line comprising a separate water passage adapted for individual communication with a water supply source, and a succession of spaced apart irrigation openings formed therein, each opening being associated with an irrigation emitter having an irrigation outlet, the irrigation outlets of the emitters of said lines being staggered with respect to each other.
The emitters used with the irrigation hose of the present invention may have any appropriate design, e.g. they may be drip irrigation emitters or mini-sprinklers. Drip Irrigation emitters may be mounted either inside the irrigation lines so as to have their irrigation outlets connected to said openings (built-in internal or in-line emitters), or outside the lines so as to have their inlets connected with said openings (external or on-line emitters). Also, different lines of the hoses and/or different openings of each line may carry different types of emitters or emitters of the same type but having different characteristics. Consequently, the two lines and/or their openings may have different diameters.
The staggered arrangement of the irrigation outlets of the emitters may be obtained in different ways. One example in accordance with the present invention is forming the hose""s irrigation lines with staggered irrigation openings and using the irrigation emitters having outlets aligned with the irrigation openings. These emitters may be in- or on-line emitters whose inlets and outlets are both aligned with the associated irrigation openings, or rather they may be in-line drip irrigation emitters whose inlets are spaced from their outlets by an elongated fluid passageway extending in the direction along the hose""s length.
Alternatively, on-line drip irrigation emitters may be used whose inlets are, and whose outlets are not, aligned with their associated openings, the outlets being spaced from the inlets by an elongated fluid passageway extending in the direction of the hose""s length.
The irrigation outlets of each irrigation line may be arranged in emitting groups including at least two adjacent outlets which may be associated with one or more irrigation emitters and with one or more openings in the irrigation line.
The emitters"" outlets or groups of outlets are preferably arranged in successive pairs of staggered outlets, and the staggered outlets of each pair are spaced by such a staggering distance as to enable their in-turn use for irrigation of a plant located therebetween. Thereby, when the outlet or group of outlets of one line are operative to irrigate the soil on one side of the plant, the outlet or group of outlets of the other line are inoperative to allow the soil on the other side of the plant to dry. However, for other irrigation regimes, the staggered arrangement of the outlets of the two lines may be different. For example, if the irrigation outlets of the two lines are used for different kinds of irrigation of the same plant, e.g. for drip irrigation and for sprinkling, the irrigation outlets are arranged so that a group of drip irrigation emitters of the drip irrigation line constitutes a pair with one or more mini-sprinkler of the sprinkling line. In this case, the outlets in each line may be spaced uniformly by distances that are different in the two lines.
It should be noted that irrigation double-passage hoses are generally known to provide two passages communication therebetween. Such a hose is disclosed, for example, in U.S. Pat. No. 4,199,106, where one passage is an irrigation or supply passage and the other one is a constant pressure passage, the passages constituting in combination one irrigation line.
With the irrigation hose according to the present invention, the two passages belong to different irrigation lines whose emitters are permanently kept in fixed mutual disposition, independent of the positioning of the hose when installed and of the maintenance of the hose, and whose installation is essentially labor saving compared with that of two separate irrigation hoses.